Since 1974, lung cancer has caused more deaths each year in the US than breast, colorectal, and prostate cancer combined. The burden of lung cancer mortality is especially high for Blacks who are even more likely than Whites to be diagnosed at the most advanced stages of the disease. For the first time, screening for lung cancer through computed tomography (CT) has been shown to reduce lung cancer mortality. The recently completed National Lung Screening Trial (NLST) concluded CT screening reduced lung cancer mortality by 20%, compared to screening with chest X-ray. CT screening in NLST reduced lung cancer mortality as much-and possibly more-for Blacks than for Whites (38% versus 14% reduction). While promising, we do not yet know if the efficacy of CT screening demonstrated in NLST will translate to effective reductions in lung cancer mortality as CT screening has now begun to occur in community practice. We also do not yet know if the benefits of CT screening will be shared equally between Black and White patients. Often the benefits demonstrated in randomized trials far exceed the benefits realized in the community. CT screening may provide less benefit to patients in the community than it did for NLST participants because of barriers to screening (e.g., low knowledge about screening and its risks) and treatment-related complications (e.g., high rates of post-operative mortality for lung cancer surgery). Moreover, if these screening barriers and treatment- related complications are higher among Blacks than Whites-as they are for other leading cancers-racial disparities in lung cancer mortality may actually widen over time. In this study, we will use data from NLST, nationally representative health survey data, and Medicare administrative claims data to address the following specific aims. First, we will generalize the findings of NLST to the US population of cigarette smokers. Second, we will assess the structural and clinical barriers facing cigarette smokers to receiving and benefiting from CT screening for lung cancer. Third, we will estimate the number of lung cancer deaths in the US that could be averted by CT screening assuming race-specific rates of CT screening and varying the effectiveness of CT screening to reduce lung cancer mortality. This project will help to improve clinical practice and narrow future racial disparities in lung cancer mortality by revealing the structural and clinical barriers that impede equally effective translation of CT screening. This project will also improve shared decision making between patients and their healthcare providers as they discuss lung cancer screening by providing the most up-to-date estimates of screening benefits and harms in everyday practice. Thus, this project will directly address key research objectives of PA-13-288. Finally, this project will inform preparation of an NCI R01 grant to assess contemporary CT screening rates in pre-Medicare and Medicare aged populations and determine if and how actual screening patterns affect disparities in stage at diagnosis, survival and lung cancer mortality at the population level.